Involute plate heat exchanger



June 14, 1966 p. E. BEAM, JR., ETAL 3,255,818

INVOLUTE PLATE HEAT EXCHANGER Filed March 9, 1964 2 Sheets-Sheet l /0 INVENTORS 5 011! 5 ee/v; (/1 24? BY 55k Z15 army/1 wye A ORNE) June 14, 1966 P. E. BEAM, JR., ETAL 3,255,818

Filed March 9, 1964 5 J m m mm m m m3 Y ATTORNEY United States Patent 3,255,818 INVOLUTE PLATE HEAT EXCHANGER Paul E. Beam, Jr., and Esten W. Spears, Jr., Indianapolis, Ind., assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Mar. 9, 1964, Ser. No. 350,283 2 Claims. (Cl. 165-166) This invention relates to heat exchangers and more particularly to toroidal heat exchangers for transferring heat from one fluid to another and especially adapted for heating combustion air for aircraft engine use by extracting heat from engine exhaust gases.

With regard to heat exchangers of the type herein considered, it is particularly advantageous to make each heat exchanger annular in form and when this is done difiiculties are encountered in compensating for variations in fluid pressure drop'and heat transfer characteristics within the cross sectional area from the inside to the outside diameter of the heat exchanger in achieving efficiency.

An object of the present invention is to provide an improved annular or toroidal heat exchanger of maximum efficiency and of simple plate construction.

A feature of the present invention pertains to a heat exchanger comprising an annular casingand a cylindrical casing joined by an interposed toroidal heat exchange means or core formed with involute plates such that the flow of fluids through the heat exchanger in the general direction of its axis may be at a more uniform rate across the cross sectional area of the core to promote maximum heat exchange efficiency.

These and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIGURE 1 is an elevation view of a combustion air duct with portions removed and showing, in longitudinal section, a heat exchanger of the present invention installed for' cooperation with the duct in extracting heat from engine combustion gases;

FIGURE 2 is a sectional view looking in the direction of the arrows 2-2 in FIGURE 1;

FIGURE 3 is a perspective view of the duct and heat exchanger of FIGURE 1 with parts broken away better to illustrate the construction; and

FIGURE 4 is an exploded view of two adjacent corrugated sections each in involute form and as utilized in the heat exchanger of FIGURES 1 to 3.

The heat exchanger of the drawings comprises an inner cylindrical casing or flow divider and an outer annular casing 12 having a common axis. Two toroidal manifolds 14 and 16 are provided each being at one end of the outer annular casing 12 and communicating with a toroidal multi-plate heat exchange means or core generally indicated at 18. The latter bridges the annular space between the casings 10 and 12 and is formulated of a series of consecutive sets of four involute plates 20, 22 and 24 and 26. Each plate 20 cooperates with a plate 24 to enclose a corrugated plate 22 and also cooperates with another plate 24 on its other side to confine a corrugated plate 26. The outer ends of the plates 20 and 24 of each set are joined at their margins as best illustrated in FIGURE 2 closely to approach the inside wall surface of the outer annular casing 12. The plates 20 and 24 are smooth surfaced, i.e. not corrugated.

FIGURE 2 also shows how the corrugated and smooth surfaced plates are nested together with inner margins 25 of the plates 24 in close contact with the outer wall of the inner cylindrical casing 10 and margins of the plates 20 resting on the margins 25 of the plates 24. Variations in the design of these details are possible without departing from the present invention.

Patented June 14, 1966 In the disclosure of FIGURE 1, the manifold 14 is served by means of an inlet conduit 30 and the manifold 16 is served by means of anoutlet conduit 32. The nested or annularly stacked plates of the heat exchange means'or core 18 are so formed as to define two alternate sets of passages extending parallel with the axis of the heat exchanger. The passages A of one of these sets provide connections or heated fluid communication between the manifolds 14 and 16 but are otherwise closed by wall portions 33 made from the plates 20. The passages of the other of the sets provide connections through the heat exchanger means 18 for handling cooler fluid flowing through a conduit 34 in paths parallel with the axis of the heat exchanger. The casing 12 includes two end rings 36 and 38 as well as two annular and frustoconical plates 40 and 42. The end plates 36 and 38 merely serve as convenient connecting plates between the manifolds 16 and 14 and the conduit 34 whereas the plates 40 and 42 are apertured as at 44 properly to connect the manifolds with the alternate passages A of the heat exchange means 18.

Alternating with the passages A are passages B and these passages B are each defined between adjacent plates 20 and 24 to handle the cooler fluid of the conduit 34. The passages A each enclose a corrugated plate 26 which progressively narrows in width toward the heat exchanger 1 axis whereas each of the passages B encloses a corrugated plate 22 which progressively increases in width toward that axis, these widths being measured in a direction parallel with the heat exchange axis. A narrow width places less restriction on fluid flow than is done by a greater width and this fact is availed of to achieve uniform flow rates regardless of at which radius each rate is measured for either of both fluids being handled.

A hot gas or fluid entering at 30 and distributed by the manifold 14 will flow through the passages A and will tend to flow along all the grooves of each of the corrugated plates 26 despite the fact that the gas is admitted and discharged near the outer periphery of the heat exchanger core. The air or other fluid to be heated passing countercurrent to the first fluid and along the conduit 34 will flow along all the grooves in each of the corrugated plates 22 although that other fluid is admitted and discharged adjacent the inner periphery of the heat exchanger means or core 18. The corrugated plates 22 and 26 not only make the flow rate of each gas more uniform throughout the cross-sectional area of the heat exchanger means but also contribute to a more intimate heat transfer relation between the fluids.

We claim:

1. A heat exchanger comprising an inner cylindrical casing and an outer annular casing, said casings having a common axis, two toroidal manifolds, one of said manifolds being positioned at each end of said outer annular casing, toroidal heat exchange means comprising an annular series of involute plates bridging the space between said casings and defining passages with each passage extending radially and outwardly from said inner casing to said outer casing and between said manifolds, alternating passages as defined by said plates connecting said manifolds and conducting one fluid, the remainder of the passages forming paths parallel to said common axis for conducting a second fluid therethrough, a corrugated involute plate in each of said passages having its width measured in the direction of the heat exchanger axis, each corrugated plate in said alternating passages progressively increasing in width from said inner casing to said outer casing and each corrugated plate in the remaining passages progressively decreasing in width from said inner casing to said outer casing so as to effect uniformity of flow rate of the fluid flowing along opposite surfaces of the corrugated involute plates.

3 2. A heat exchanger as set forth in claim 1 wherein said outer annular casing includes a pair of frusto-conical plates having apertures for communicating said one fluid between said toroidal manifolds and said alternating passages.

References Cited by the Examiner UNITED STATES PATENTS 721,310 2/1903 Junkers 165-161 2,354,698 8/1944 Morris 165166 2,516,910 8/1950 Redding 6039.51 X 2,646,027 7/1953 Ackerman et al. 165166 X 3,098,522 7/1963 McCormick 165166 3,166,122 1/1965 Hryniszak 165166 X FOREIGN PATENTS 5 276,761 4/ 1927 Great Britain. 581,742 10/ 1946 Great Britain.

ROBERT A. OLEARY, Primary Examiner.

10 CHARLES SUKALO, Examiner.

T. W. STREULE, Assistant Examiner. 

1. A HEAT EXCHANGER COMPRISING AN INNER CYLINDRICAL CASING AND AN OUTER ANNULAR CASING, SAID CASINGS HAVING A COMMON AXIS, TWO TOROIDAL MANIFOLDS, ONE OF SAID MANIFOLDS BEING POSITIONED AT EACH END OF SAID OUTER ANNULAR CASING, TOROIDAL HEAT EXCHANGE MEANS COMPRISING AN ANNULAR SERIES OF INVOLUTE PLATES BRIDGING THE SPACE BETWEEN SAID CASINGS AND DEFINING PASSAGES WITH EACH PASSAGE EXTENDING RADIALLY AND OUTWARDLY FROM SAID INNER CASING TO SAID OUTER CASING AND BETWEEN SAID MANIFOLDS, ALTERNATING PASSAGES AS DEFINED BY SAID PLATES CONNECTING SAID MANIFOLDS AND CONDUCTING ONE FLUID, THE REMAINDER OF THE PASSAGES FORMING PATHS PARALLEL TO SAID COMMON AXIS FOR CONDUCTING A SECOND FLUID THERETHROUGH, A CORRUGATED INVOLUTE PLATE IN EACH OF SAID PASSAGES HAVING ITS WIDTH MEASURED IN THE DIRECTION OF THE HEAT EXCHANGER AXIS, EACH CORRUGATED PLATE IN SAID ALTERNATING PASSAGES PROGRESSIVELY INCREASING IN WIDTH FROM SAID INNER CASING TO SAID OUTER CASING AND EACH CORRUGATED PLATE IN THE REMAINING PASSAGES PROGRESSIVELY DECREASING IN WIDTH FROM SAID INNER CASING TO SAID OUTER CASING SO AS TO EFFECT UNIFORMITY OF FLOW RATE OF THE FLUID FLOWING ALONG OPPOSITE SURFACES OF THE CORRUGATED INVOLUTE PLATES. 